Involvement of prostaglandins and histamine in radiation-induced temperature responses in rats.
Exposure of rats to 1-15 Gy of gamma radiation induced hyperthermia, whereas exposure to 20-150 Gy produced hypothermia. Since radiation exposure induced the release of prostaglandins (PGs) and histamine, the role of PGs and histamine in radiation-induced temperature changes was examined. Radiation-induced hyper- and hypothermia were antagonized by pretreatment with indomethacin, a cyclooxygenase inhibitor. Intracerebroventricular administration of PGE2 and PGD2 induced hyper- and hypothermia, respectively. Administration of SC-19220, a specific PGE2 antagonist, attenuated PGE2- and radiation-induced hyperthermia, but it did not antagonize PGD2- or radiation-induced hypothermia. Consistent with an apparent role of histamine in hypothermia, administration of disodium cromoglycate (a mast cell stabilizer), mepyramine (H1-receptor antagonist), or cimetidine (H2-receptor antagonist) attenuated PGD2- and radiation-induced hypothermia. These results suggest that radiation-induced hyperthermia is mediated via PGE2 and that radiation-induced hypothermia is mediated by another PG, possibly PGD2, via histamine.
Kandasamy
S B
SB
Behavioral Sciences Department, Armed Forces Radiobiology Research Institute, Bethesda, Maryland 20814-5145.
Hunt
W A
WA
D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology / Q000528:radiation effects*; D003037:Cobalt Radioisotopes; D015232:Dinoprostone / Q000502:physiology*; D005720:Gamma Rays; D006632:Histamine / Q000502:physiology*; D008297:Male; D015230:Prostaglandin D2 / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D003037:Cobalt Radioisotopes; D006632:Histamine; D015232:Dinoprostone; D015230:Prostaglandin D2